cc: Fix PostiveRatio crash by checking raster scale

cc: Fix PostiveRatio crash by checking raster scale

The first time through ManageTilings, raster scale is zero, so you can't
use it to find a ratio.  This DCHECKS because the ratio is infinite.
If the raster scale is zero, we already create new tilings, so skipping
this check will just avoid the DCHECK.

R=reveman@chromium.org
BUG=174236
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=181857

[reveman, 2013-02-11 22:45:52]

lgtm

[commit-bot: I haz the power, 2013-02-11 22:53:17]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/12209103/1

[danakj, 2013-02-11 23:11:35]

Thanks for fixing this.

https://chromiumcodereview.appspot.com/12209103/diff/1/cc/picture_layer_impl.cc
File cc/picture_layer_impl.cc (right):

https://chromiumcodereview.appspot.com/12209103/diff/1/cc/picture_layer_impl....
cc/picture_layer_impl.cc:573: if (is_active_layer && is_pinching &&
raster_page_scale_) {
I guess all of these if()s could be guarded by (...&& !change_target_tiling) to
deal with this, and ensure only the last positive case happens.

But I guess this way is also more ordering-independent for better or worse.

[commit-bot: I haz the power, 2013-02-12 02:14:23]

List of reviewers changed. danakj@chromium.org did a drive-by without LGTM'ing!

[enne (OOO), 2013-02-12 02:18:20]

https://chromiumcodereview.appspot.com/12209103/diff/1/cc/picture_layer_impl.cc
File cc/picture_layer_impl.cc (right):

https://chromiumcodereview.appspot.com/12209103/diff/1/cc/picture_layer_impl....
cc/picture_layer_impl.cc:573: if (is_active_layer && is_pinching &&
raster_page_scale_) {
On 2013/02/11 23:11:35, danakj wrote:
> I guess all of these if()s could be guarded by (...&& !change_target_tiling)
to
> deal with this, and ensure only the last positive case happens.
> 
> But I guess this way is also more ordering-independent for better or worse.

Or put it all in a helper function? Anyway, I'm just trying to fix this crash
for now, so am going to land this as-is.

[commit-bot: I haz the power, 2013-02-12 02:19:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/12209103/1

[commit-bot: I haz the power, 2013-02-12 04:56:48]

Change committed as 181857